Electric-arc lamp



(No Model.) R. S. BOBBIE.

ELECTRIC ARC LAMP.

No. 469,041. 7 Patented Feb. 16, 1892.

wilmeoom UNITED STATES PATENT OF ICE.

ROBERT S. DOBBIE, OF JERSEY CITY, NEW JERSEY.

ELECTRIC-ARC vLAM P.

SPECIFICATION forming part of Letters Patent No. 469,041, dated February 16, 1892.

Application filed October 28. 1890- Seria1No. 369,080. (N0 model.) I

To all whom it may concern.-

Be it known that I, ROBERT S. DOBBIE, a citizen of the United States, and a resident of Jersey City, in the county of Hudson and State of. New Jersey, have invented a new and useful Improvement in Are Lamps, of which the following is a specification.

My object is to produce an arc lamp wherein the feed will be smooth and even, the are if broken will be automatically re-formed, and wherein if in case two or more lamps be arranged in series for any reason the feed be interrupted a shunt around the lamp capable of sustaining the full flow of current indefinitely will be firmly closed. I accomplish these objects, as well as general smoothness and reliability of operation, by operating a brake by a system of toggles so arranged that the maximum increase of force is obtained when the brake-shoe is 1n contact by uslng similar toggles to close the contacts for the; shunt around the lamp, and by damping a feed-disk by Foucault currents set up by magnets that are preferably excited by the same current that passes through the arc.

To these ends my inventio'n consists of the several apparatus constructed, arranged, and combined substantially in the manner hereinafter described, illustrated, and claimed, reference being bad to the accompanying drawings, wherein Figure l is a'general diagrammatic view of my invention; .Fig. 2, a detail View of certain parts; and Fig. 3 is'a View of a modification.

Like reference-letters indicate like parts in the several views.

Ihave preferred to show my apparatus diagrammatically, because the relative position and association of the several mechanisms, though of great practical. importance, are for- So the many mechanical supports and guides are omitted for the sake of clearness as being matters to be determined solely by choice or by mechanical economies.v

As illustrated in Figs. 1 and 2, O O are the.

' braked by a brake B, is secured coaxially to the pinion P on lever L. The pinion P is prevented from turning relatively to the disk D in the direction to feed the carbon bya pawl and ratchet, also coaxially secured. This ratchet enables .the holder to be pushed up by the lamp tender for the insertion of new carbon or for similar matters. It may, however, be omitted in many cases, as where means K are provided for retracting the brake.

That there may be little lateral motion between the periphery of the disk and the brakeshoe the lever L is preferably fulcru med near the latter. Its other end,which is supported when the lamp is not in operation by an adjustable stop, carries the armature A for my starting-magnet M. This when drawn up by the magnet forms the arc in the usual way. My magnet M is of peculiar construction and serves the double function of an arc-forming magnet and of an electromagnetic damper for my feed-disk D. This I'accomplish by dividing my magneticcircuit at the rear and presenting salient poles to each face of the disk. The Foucault currents generated by the motion of the conducting-disk serve effectually to dampen its'rotation. If it be found desirable to increase this effect, one or more supplemental magnets M in the same circuit may be employed' By. the term magnet I include any field-producing agency whatsoever used for my purpose; also, since it is clear that the damping-poles might have other relative position in the magnet M, I do not limit myself to poles placed at the rear of the magnet. I prefer, however, as shown, to form this magnet of the two cores having two exciting-coils and. so located that when the armature A is drawn up there will be a practically-continuous horseshoe-magnet, presenting strong damping-poles to the disk D. To avoid the possibility of the armature A sticking to this magnet M, which, if lever L were light, might sometimes occur, I may use any of the well-known means of preventing my armature from making actual contact with the polar faces of'magnet M.

Mybrake-shoe Bis attached to a toggle- ;joint T, placed in such position that the toggles will be nearly in a line when the brake is on. The brake is put on by the operation at O and the low shunt put around the lamp.

This will only be when the difference of potential between terminals has grown abnormally large, as when the feed or the arc itself is interrupted. In such cases upon restoring the arc thecurrentflowin g through the sh untcoils s will be so far reduced that the contacts :0 will again open and the normal condition of the lamp be resumed. To insure this relation it will in most cases be necessary -;to add the resistance I to the shunt 5''. If it be desired, the shunt .9 may equal the resistance of .the arc, and thus the .action just set forth have .no effect .on the other parts of the circuit. In any case the shunt 3' should beeapable of carrying the full current indefinitely. In such instances I also provide aconnection 0, closing the circuit through .9 at f, :while the lever L rests on its stop.

The moclus opercmdt' of this form'of- .m y apparatus is asfollows: vWhile thelamp is not in use thecarbonsC and-C'are in contact and the brake firmlyapplied by the spring II. IVhen the current is turned on, the magnet Mat once forms thearc. As the'arc lengthens, the difference of potential betweenterminals increases andzwith it the sh-unt-currentin 8. Thus the pressure on thebrakeis gradually removed, till finally the brake slips and the disk D rotates. The motion is not, however, free, for besides the friction of the brake itself the dampingmagnets effectually retard the rotation that it is .as though the disk were immersed in some viscous fluid. As the feed continues, the are is shortened and its resistance accordingly reduced. XVith this occurs a fall of lamp potentialand a consequent reduction of the shunt-current, which thus again allows the :brake to act. This is the normal operation. :In the case of .constant current circuits, for which the form of lamp illustrated is especially adapted, there are three chief causes that interrupt this normal operation. The first is wherea gust of wind ruptures the are. In this case the current momentarily flows round the shunt s; but this ,almost instantaneously closes the shunt s, which remains closed till the carbons again touch. In this case, also, the damper and brake are both automatically non-acting and the feed and restoration of the .arc accordingly quicker. Upon the carbons touching, the current is so far shunted from s, that the spring 11 breaks the contact 0 and restores the normal operation. Another cause is the interference of the feed by foreign particles or its becoming out of order. In this case the shunts act as in the first case and the current flows through 3 till the feed is resumed. A third cause is when the lamp is about burned out, and the end of rack R, reaching the pinion 1 allows the carbons to form a permanent closed connection in the usual manner. \Vith constantpotential circuits no such provision for shunting the current is needed unless several lamps are run in series together, and in place of allowing the carbons'to come together permanently at the end of the rack-feed astop may be used, as is now usually donein such cases.

By the foregoing description I have set forth one form of my complete device. Itis, however, obvious that my novel features may with slight change be applied to many other types of are lamp. Fig. 3 shows one such modification, in which my toggle-brake is utilized in a lamp of the type in which the length of are is adjusted by the differential action of main and shunt solenoids. My lever L in this form carries the toggles T and actuating-spring H for applying the brakecluteh to the-smooth holder-rod R. ver L is pivoted at or. near its center and bears at the end remote from R the solenoid armature A". S is the shunt-solenoid tending to shorten the arc, while M is the series magnet which draws the arc and which tends to increase its length. The action of these magnets need not be further explained, as they are well known. When the carbons burn away and feed is required, the lever L reaches such position that a projection t on the toggles comes in contact-with a stop t and withdraws or lessens the brake-pressure. As the carbon thereupon falls, the brake end of the lever rises,-and the brake thereby released catches the sliding rod at somewhat above its former position. This occurs beforethe latter has fallen appreciably. The solenoid S contains the open-eircuited safety-shunt s, as more fully indicated in Fig. 2, which may be operated by the armature-core A" in the same way.

It is often necessary to have but small resistance in the external circuit of a plant at starting in order that the proper pressure and current may be established-in the dynamos. In such instances, if the carbons be apart, the current cannot build up unless some temporary path is afforded it. I have therefore addedthe circuit connections 0', referred to above. It will be seen that a closed connection of low resistance is thereby established at starting, and in this the initial current may build itself .up until by the withdrawal of the brake the carbons meet and the arc is struck, thus breaking the initial circuit at A.

I will not attempt to detail at length the many variations that may be made in the parts of my apparatus.

The solenoids in the figures may be replaced by other magnetic means -such, for instance, as magnetsand by the term so- The lelenoid in the claims Iinolude all such modifications. .So by the term magnets I include any known magnetic means having like functions. In the other details, also,

.many modifications may be made; but all tations than those hereunder named-- 1. In combination with the other operating parts of an arc lamp, a feed-disk, a brake therefor, springtoggles for operating the brake, a solenoid included between the terminals of the lamp, an armature therefor attached to the said toggles for retracting the brake, a second shunt winding on said solenoid open-circuited at contacts 0, toggles for closing the said contacts and actuated by the said solenoid against the action of a spring, and the starting-magnet M, presenting salient poles to the faces of the feed-disk, as and for the purposes set forth.

2. In combination with the other operating parts of an arc lamp, a feed-disk',a'brake therefor actuated by spring-toggles against the action of ashunt-solenoid, a second set of toggles actuated by the said solenoid against the detracting action of the braketoggle spring to close contact at O, and a shunt connection around the lamp normally open-circuited at contacts 0, as and for the purposes set forth.

3. In combination, in an arc lamp, a conducting feed-disk, starting mechanism provided with an arcstriking magnet or magnets and armature, the said magnet or magnets presenting opposing poles to the opposite faces of the said disk, and the said armature forminga part of the magnetic circuit of such magnets passing through the said disk, substantially as and for the purposes set forth.

4. In combination, in an arc lamp, a conducting feed-disk, a support for the same, one or more starting-magnets for striking the are, adapted to produce one or more fields of force through the feed-disk, and one or more supplemental magnets for producing similar fields in the feed-disk, substantially as set forth.

In testimony hereof I affix my hand, this 21st day of October, A. D. 1890, in the presence of the subscribing witnesses.

. ROBERT S; BOBBIE.

WVitnesses:

HAROLD BINNEY, WALTER WARD. 

